Criminologists who examine prison siting and proliferation often take two approaches. On one hand, researchers explore citizens’ perceptions of prison siting in their community. Alternatively, they unpack consequences a prison brings to a region—often with attention toward whether they fuel economic growth. This discussion occasionally invokes the concept environmental sociologists commonly used to examine environmental injustices: LULUs (locally undesirable land uses). However, criminologists have not drawn on this concept to consider how environmental contamination and prison proliferation dovetail in the context of mass incarceration. Relatedly, environmental justice scholars have begun to suggest that prisons are rife with environmental justice issues that scholars in that subdiscipline should take seriously. Here, we draw these subfields into conversation with one another, as we see several important synergies. In particular, we heed Eason’s (2017, Big House on the Prairie: Rise of the Rural Ghetto and Prison Proliferation . Chicago, IL: University of Chicago Press) call for a more robust theoretical framework interrogating the causes and consequences of the prison boom by making a case that environmental justice work on LULUs provides criminology an opportunity to understand prison proliferation more critically. In turn, we make the case that environmental justice scholars have inroads into the study of mass incarceration—especially as it relates to prison proliferation.